Sumidero Canyon
Encyclopedia
Sumidero Canyon is a narrow and deep canyon surrounded by a national park located just north of the city of Tuxtla Gutiérrez
Tuxtla Gutiérrez
Tuxtla Gutiérrez is the capital and largest city of the Mexican state of Chiapas. It is considered to be the state’s most modern city, with most of its public buildings dating from the 20th century. One exception to this is the San Marcos Cathedral which began as a Dominican parish church built in...

 in the Mexican state of Chiapas
Chiapas
Chiapas officially Estado Libre y Soberano de Chiapas is one of the 31 states that, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 118 municipalities and its capital city is Tuxtla Gutierrez. Other important cites in Chiapas include San Cristóbal de las...

. The canyon’s creation began around the same time as the Grand Canyon
Grand Canyon
The Grand Canyon is a steep-sided canyon carved by the Colorado River in the United States in the state of Arizona. It is largely contained within the Grand Canyon National Park, the 15th national park in the United States...

 in the U.S. state of Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...

, by a crack in the area’s crust and erosion by the Grijalva River
Grijalva River
Grijalva River, formerly known as Tabasco River. is a 480 km long river in southeastern Mexico. It is named after Juan de Grijalva who visited the area in 1518. The river rises in Chiapas highlands and flows from Chiapas to the state of Tabasco through the Sumidero Canyon into the Bay of...

, which still runs through it. The canyon has vertical walls which reach as high as 1000 meters, with the river turning up to ninety degrees during the thirteen kilometers that the narrow passage runs. At the north end of the canyon is the Chicoasén Dam
Chicoasén Dam
The Chicoasén Dam is an embankment dam and hydroelectric power station on the Grijalva River near Chicoasén in Chiapas, Mexico. The dam's power plant, known as "Manuel Moreno Torres" contains 5 x 300 MW, 3 x 310 MW Francis turbine-generators. Torres was Comisión Federal de Electricidad's Director...

, one of several on the Grijalva River and important for water storage and the generation of hydroelectricity. Surrounding the canyon is the Sumidero Canyon National Park, which extends for 21,789 hectares over four municipalities of the state of Chiapas. This park is administered by the Comisión Nacional de Áreas Naturales Protegidas (Conanp). Most of the vegetation of this park is low to medium height deciduous
Deciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...

 rainforest
Rainforest
Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...

, with small areas of pine/oak trees and grassland.

The canyon/park is the second most important tourist site in Chiapas, drawing mostly Mexican visitors who see the canyon by boats which leave from Chiapa de Corzo
Chiapa de Corzo, Chiapas
Chiapa de Corzo is a small city and situated in the west-central part of the Mexican state of Chiapas. Located in the Grijalva River valley of the Chiapas highlands, Chiapa de Corzo lies some 15 km to the east of the state capital, Tuxtla Gutiérrez...

. The park borders Tuxtla Gutiérrez, the state’s largest city, which has caused problems with human encroachment and settlement on park land. More importantly, the urban areas and logging areas upstream from the canyon have caused serious pollution problems, with up to 5000 tons of solid waste extracted from the Grijalva River each year. This waste tend to build up in the canyon because of its narrowness, the convergence of water flows and the presence of the Chicoasén Dam.

Description

The Sumidero Canyon was formed by cracks in the earth’s crust along with erosion by the Grijalva River
Grijalva River
Grijalva River, formerly known as Tabasco River. is a 480 km long river in southeastern Mexico. It is named after Juan de Grijalva who visited the area in 1518. The river rises in Chiapas highlands and flows from Chiapas to the state of Tabasco through the Sumidero Canyon into the Bay of...

, which still flows through it. The process of its formation began about 35 million years ago, making the Sumidero contemporary with the Grand Canyon
Grand Canyon
The Grand Canyon is a steep-sided canyon carved by the Colorado River in the United States in the state of Arizona. It is largely contained within the Grand Canyon National Park, the 15th national park in the United States...

 on the Colorado River
Colorado River
The Colorado River , is a river in the Southwestern United States and northwestern Mexico, approximately long, draining a part of the arid regions on the western slope of the Rocky Mountains. The watershed of the Colorado River covers in parts of seven U.S. states and two Mexican states...

 . The Grijalva is the main water system in the area, beginning in the Cuchumatanes in Guatemala. The river then flows through Chiapas, including the thirteen km length of the canyon from south to north then onto Tabasco
Tabasco
Tabasco officially Estado Libre y Soberano de Tabasco is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 17 municipalities and its capital city is Villahermosa....

 before it empties into the Usumacinta River
Usumacinta River
The Usumacinta River is a river in southeastern Mexico and northwestern Guatemala. It is formed by the junction of the Pasión River, which arises in the Sierra de Santa Cruz and the Salinas River, also known as the Chixoy, or the Negro, which descends from the Sierra Madre de Guatemala...

. This river basin is one of the two most important in Chiapas, and one of the most important in Mexico with a total river length of 766 km, draining an area of 7,940km2, with an average flow of about forty million cubic meters.

In addition to the Grijalva, there are other flows of water in the area in and around the canyon, many of which are seasonal. These consists of streams, some of which form waterfalls on the canyon’s sides and underground movements which have created caves and karst formations. The last important water formation in the area is the reservoir of the Chicoasén Dam
Chicoasén Dam
The Chicoasén Dam is an embankment dam and hydroelectric power station on the Grijalva River near Chicoasén in Chiapas, Mexico. The dam's power plant, known as "Manuel Moreno Torres" contains 5 x 300 MW, 3 x 310 MW Francis turbine-generators. Torres was Comisión Federal de Electricidad's Director...

, which is manmade.

The canyon proper is deep and narrow, characterized by vertical walls. As the gap changes direction as much as 90 degrees in places, it separates the Meseta de las Animas mesa
Mesa
A mesa or table mountain is an elevated area of land with a flat top and sides that are usually steep cliffs. It takes its name from its characteristic table-top shape....

 in the west from the Meseta de Ixtapa mesa in the east. The width of the canyon varies from one to two kilometers. Most of the canyon’s walls are between 200 and 700 meters high reaching 1000 meters at its highest point. These walls expose a long process of disturbances in the Earth’s crust here with layers of limestone from the Upper Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...

, which have fossils of marine creatures. During the Mesocretac Period, there was an elevation of ocean floor which formed much of the mountains of the area.

The interior of the canyon has thirty rapids, five waterfalls, three beaches, two freshwater springs and a cofferdam
Cofferdam
A cofferdam is a temporary enclosure built within, or in pairs across, a body of water and constructed to allow the enclosed area to be pumped out, creating a dry work environment for the major work to proceed...

 three meters wide. The canyon contains endangered and threatened species such as the Central American river turtle and the American crocodile
American Crocodile
The American crocodile is a species of crocodilian found in the Neotropics. It is the most widespread of the four extant species of crocodiles from the Americas. Populations occur from the Atlantic and Pacific coasts of southern Mexico to South America as far as Peru and Venezuela. It also lives...

, which can be seen on the riverbanks. The walls of the canyon contain small caves, rock formations and other notable features. The best known of the area’s caves is the Cueva de Colores (Cave of Colors). This cave gets its name from the filtration of magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...

, potassium
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...

 and other minerals which form colors on the walls, especially shades of pink. It contains an image of the Virgin of Guadalupe inside usually surrounded by fresh flowers and burning candles left by visitors. The Cueva de Silencio (Cave of Silence) is named such because of a lack of echo or any other kind of resonance in its interior. In another small cave, there is a stalactite
Stalactite
A stalactite , "to drip", and meaning "that which drips") is a type of speleothem that hangs from the ceiling of limestone caves. It is a type of dripstone...

 called the Caballito de Mar or Seahorse after its shape. Of the various seasonal waterfalls, the best known is the Árbol de Navidad (Christmas Tree). The “branches” of the Árbol are made by deposits from the waterfall which have are then covered in moss. During the rainy season, when the waterfall is active, the water and the light changes the colors of the “branches” and makes the formation stand out more. The park was a candidate in 2009 as one of the Seven New Natural Wonders of the World
Seven Natural Wonders (CNN)
Seven Natural Wonders is a project created with the mission of protecting and promoting the original seven natural wonders of the world. The project was launched in 2008 in response to the New 7 Wonders efforts to change the natural wonders of the world...

 .

Pollution problems

Via the Grijalva River, the wastewater of about 552,000 people in seventeen municipalities finds its way through the canyon according to park director Edda González del Castilla, with most coming from Tuxtla Gutiérrez, Chiapa de Corzo
Chiapa de Corzo
Chiapa de Corzo may refer to:*Chiapa de Corzo - a Mesomerican archaeological site located in the Chiapas highlands, Mexico*Chiapa de Corzo, Chiapas - the modern township and municipality, central Chiapas, Mexico...

, Berriozábal
Berriozábal
Berriozábal is a town and one of the 119 Municipalities of Chiapas, in southern Mexico.As of 2005, the municipality had a total population of 28,719. It covers an area of 300.6 km²....

 and Chicoasén
Chicoasén
Chicoasén is a town and one of the 119 municipalities of Chiapas, located in southern Mexico.As of 2005, the municipality had a total population of 3,346. It covers an area of 82 km²....

 . Much of the sewerage comes into the Grijalva via the Sabinal River
Sabinal River
The Sabinal River is a river in Texas. During exceptional drought large portions of this river may flow underground, with scattered pools of surface water.-References:**USGS Hydrologic Unit Map - State of Texas...

, which carries most of the waste water of the city of Tuxtla Gutiérrez. In addition, trash and raw sewerage makes its way into the river from the various tributary streams. Agricultural waste comes from the farms that line the river and its tributaries.

The most obvious pollution is garbage, especially plastic containers, which mostly comes from area homes and businesses tossed onto the ground or in streams, especially from Chiapa de Corzo and Tuxtla Gutiérrez due to the lack of environmental awareness according to Conanp. The quantity of this trash reaches its height during the rainy season, when runoff and swollen streams can carry more of it into the Grijalva. While bottles and other plastic are what the casual visitor generally notices, other indicators include the overgrowth of water lilies
Water lily
The phrase "water lily" is used to describe aquatic plants of the following families, which have lily pads:* Nymphaeaceae* Nelumbonaceae , also called "lotus"Water lily may also refer to:...

 (due to high levels of fecal matter) and dead animals. However, this accounts for only about five percent of the total tonnage of waste that comes into the river each year. Somewhere between 80 and 90% of the waste solids found in the river is branches, wood, rocks, sediment and other debris from legal and illegal logging, which cause deforestation
Deforestation
Deforestation is the removal of a forest or stand of trees where the land is thereafter converted to a nonforest use. Examples of deforestation include conversion of forestland to farms, ranches, or urban use....

 . These mostly come into the river during the rainy season, especially from the Villa Flores and Villa Corzo
Villa Corzo
Villa Corzo is a town and one of the 119 municipalities of Chiapas, in southern Mexico.The only urban area is the Villa Corzo City ....

 municipalities. Only a small part of the solid waste is visible on the surface of the water, most is hidden underneath.

As the solids flow along the Grijalva, they are constricted by the narrow channel of the canyon and then by the presence of the Chicoasén Dam. This is particularly true at a point called “El Tapón” (The Plug), where two currents of water meet just before the reservoir back up of water from the Dam.

It is estimated that about 5000 tons of trash accumulate each year, and the river is considered to be one of the five most polluted in Mexico. 3700 tons of solids were extracted from the canyon area in 2010 alone. Many fish have died off or have developed abnormally due to contamination by fertilizers, pesticides and other chemicals. This threatens the native American crocodiles as the agrochemicals kill off and poison the fish they need to eat. In May 2011, the Fédération Internationale de Natation decided cancel its annual swim marathon in the canyon as they claimed that pollution levels in the river posed a risk to swimmers’ health. The Comisión Nacional del Agua and the government of Chiapas disputed this, presenting their own test results stating that levels were below such levels.

There are year-round and seasonal efforts to clean the river within the canyon and the area just upstream from it. Much of the daily effort is undertaken by workers with the Comisión Nacional de Áreas Naturales Protegidas (Conanp) and the Secretariat of Tourism in Chiapas, which extract twelve tons of garbage from the Grijalva river each day. Most of the season cleanup coincides with the rainy season, especially in September and October, when rains are heaviest. This seasonal effort has included local police, civil protections agencies, social organization, the army and individual volunteers. Efforts can involve up to 600 people at a time using 32 boats from four of the tourist cooperatives. During the annual campaign to clean the canyon in 2005 more than 60,000 tons of trash was removed. Generally, about forty tons of garbage is collected each day during these campaigns.

While the cleanup efforts have improved the situation in the canyon, the garbage reaccumulates especially during the rainy season. Part of the price that tourists pay for boat rides into the canyon pays for cleanup efforts, but the boat operators state that the canyon remains filled with trash. Conanp also states that cleanup efforts are insufficient. Mexico’s federal environmental agency, the Secretaría de Medio Ambiente y Recursos Naturales (Semarnat) states that it cannot get involved in the situation as it is the municipalities that have the responsibility for disposing of trash appropriately. However, many of these local governments do not have landfills or the separation of recyclables.

Chicoasén Dam

At the northern end of the Sumidero Canyon is the Chicoasén Dam
Chicoasén Dam
The Chicoasén Dam is an embankment dam and hydroelectric power station on the Grijalva River near Chicoasén in Chiapas, Mexico. The dam's power plant, known as "Manuel Moreno Torres" contains 5 x 300 MW, 3 x 310 MW Francis turbine-generators. Torres was Comisión Federal de Electricidad's Director...

, formally called the Manuel M. Torres Dam, is one of a number of dams which have been built along the Grijalva River for water storage and the generation of hydroelectric power. This dam and its reservoir is considered to be part of the Sumidero Canyon system. The Sumidero Canyon National Park is defined on the north end of the river by this dam and the Belisario Domínguez Bridge on the south. The dam was constructed between 1974 and 1980. The reservoir covers an average of 2,193 hectares, and the complex employs about 600 workers.

The Chicoasén Dam produces electricity and manages the flow of the Grijalva river along with the Hondo River and the Muñiz, El Jardín and El Cacao streams, which converge to form the Osumacinta River. This reservoir is one of the most important in the country. The hydroelectric station is also one of the most important in the country with thirty generators with the potential to generate 3,928.48 megawatts, with an average of 5,749.99 gigawatts per hour. This is just over thirty percent of all hydroelectric energy produced in Mexico.

Establishment of the park

The Sumidero Canyon National Park has its origins in a Chiapas state decree issued in 1972, which made the area around the canyon a ecological reserve to preserve its geology, history and wildlife and to allow for scientific study. For similar reasons, the park was taken over and enlarged to 21,789 hectares by the federal government in 1980. Most private landholders in the area were compensated for their lands, but not all resident persons or businesses were evicted. Since that time, the park has been under the administration of various agencies such as SAHOP, SEDUE and SEMARNAP, with the current managers, the Comisión Nacional de Áreas Naturales Protegidas and the Secretaría de Educación Pública
Secretaría de Educación Pública
The Secretaría de Educación Pública is a Mexican federal government authority with Cabinet representation and responsibility for overseeing the development and implementation of national educational policy and school standards in Mexico.Additionally, it has the following responsibilities:*Creation...

. In 2004, the park came under the protection of the Ramsar Convention
Ramsar Convention
The Ramsar Convention is an international treaty for the conservation and sustainable utilization of wetlands, i.e., to stem the progressive encroachment on and loss of wetlands now and in the future, recognizing the fundamental ecological functions of wetlands and their economic, cultural,...

 due to the importance of its ecology and water systems. It was also named a Región Prioritaria Terrestre and an Área de Importancia para la Conservación de las Aves by the Comisión Nacional para el Conocimiento y Uso de la Biodiversidad (Conabio) in 2000. In 2005 and 2006, this agency enlarged the park again with the expropriation of lands in the municipality of San Fernando
San Fernando, Chiapas
San Fernando is a town and one of the 119 Municipalities of Chiapas, in southern Mexico.As of 2005, the municipality had a total population of 26,436. It covers an area of 258.3 km²....

 and municipality of Tuxtla Gutiérrez, adding a total of 1660 hectares. It remains, however, smaller than most other national parks in Mexico.

The center of the park is the Sumidero Canyon and the Grijalva River that runs from south to north through it. The parks borders on this river are marked by the Belisario Domínguez Bridge, over which the Pan American Highway runs, in the south and the Chicoasén Dam, 35 km to the north. The rest of the park’s borders extend into the municipalities of Tuxtla Gutiérrez, Chiapa de Corzo, Osumacinta
Osumacinta
Osumacinta is a town and one of the 119 Municipalities of Chiapas, in southern Mexico.As of 2005, the municipality had a total population of 3,132. It covers an area of 221.1 km²....

 and San Fernando. This territory is mostly located in the Central Valley region of the state. The park is open 365 days a year. The park is divided into four sections by direction. The northwest includes medium height, somewhat deciduous rainforest as well as some lowland rainforest and grassland, found in the municipalities of Osumacinta and San Fernando. The west portion has similar vegetation, and is located entirely in San Fernando. The east portion has forests of pine as well as medium height semi deciduous rainforest and grasslands. This is found in Chiapa de Corzo. The southeast has most of the sides of the canyon itself, a navigable section of the Grijalva River but with only remnants of medium height rainforest and pachycaulous vegetation.The main land access into the park is from Tuxtla Gutiérrez north through Osumacinta then past the Chicoasén Dam. Another access is from Chiapa de Corzo by boat from the Cahuaré Docks. As the main attraction of the park is the canyon, several lookout points have been constructed in various parts of the rim. La Ceiba is closest to the city of Tuxtla Gutiérrez, only eight km away. The Los Chiapas point is near where the canyon’s walls rise highest from the river below, where according to legend, a number of Chiapa people preferred to commit suicide by jumping rather than submit to Spanish domination. This lookout also has a restaurant.

Climate and vegetation

Despite its biological, ecological and cultural diversity, there have been few studies performed within the park area. For this reason, there is a lack of information about species, habitats and water flow. There is also relatively little information about how human activities affect the park.

As the park is located in the Central Valley of Chiapas and borders the Northern Mountains region, altitudes vary from 600 meters above sea level in the municipality of Chiapa de Corzo to 1200 masl at the El Roblar lookout point. This geography produces a channel for air flow from northwest to southeast as well as three main climates based on the Köeppen system
Köppen climate classification
The Köppen climate classification is one of the most widely used climate classification systems. It was first published by Crimea German climatologist Wladimir Köppen in 1884, with several later modifications by Köppen himself, notably in 1918 and 1936...

 as modified for Mexico. These are hot and dry (where airflow is blocked); semi hot and humid and hot and humid. The average rainfall for the park is about 1,000 mm during the rainy season from May to October and 200 mm during the dry season from November to April. Average annual temperature is 26C. The rugged terrain also makes of a number of microclimates.
Most of the park’s vegetation, especially around the canyon is rainforest. Most species found in the park include those of the Fabaceae
Fabaceae
The Fabaceae or Leguminosae, commonly known as the legume, pea, or bean family, is a large and economically important family of flowering plants. The group is the third largest land plant family, behind only the Orchidaceae and Asteraceae, with 730 genera and over 19,400 species...

 family with 59 species and the Asteraceae
Asteraceae
The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...

 family with 25 species, which reflect the abundance of these families statewide. Another important family is the Orchidaceae
Orchidaceae
The Orchidaceae, commonly referred to as the orchid family, is a morphologically diverse and widespread family of monocots in the order Asparagales. Along with the Asteraceae, it is one of the two largest families of flowering plants, with between 21,950 and 26,049 currently accepted species,...

 and Euphorbiaceae
Euphorbiaceae
Euphorbiaceae, the Spurge family are a large family of flowering plants with 300 genera and around 7,500 species. Most are herbs, but some, especially in the tropics, are also shrubs or trees. Some are succulent and resemble cacti....

, each with 22 species, the Canvolvulaceae family with seventeen species and the Cactaceae with eleven species. 122 species are considered valuable as ornamental plants with 46 having medicinal use and 31 species can be logged. These mostly come from the rainforest areas. Most rainforst vegetation is mostly deciduous, shedding leaves in the dry season. However, there are perrenial rainforests, forests of pine and oak, grassland (mostly induced) and areas with secondary vegetation.

The three main vegetation classifications are low height rainforest, medium height rainforest (as per the size of the trees), oak-pine forest and meadows. Medium height deciduous rainforest is mostly located on either side of the canyon, in the north and east of the part towards San Fernando and in the Cañada Muñiz at altitudes of between 150 and 1250 masl. It is mostly found in areas with basalt
Basalt
Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...

 or granite
Granite
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...

 rock and where there are lime deposits, covering an area of 11,382 hectares in total. While many plants here loose leaves in the dry season, there are some that retain them year round. Maximum height of trees varies between twenty five and thirty meters. The density of the tree cover in these areas is enough to lower temperatures on the ground in the summer rainy season due to the maximum foliage which occurs at this time. The tree cover is composed of the following species, breadnut (Brosimum
alicastrum), guanacaste (Enterolobium cyclocarpum), totoposte (Licania arbórea), jocotillo
(Astronium graveolens
Astronium graveolens
Astronium graveolens is a species of flowering tree in the cashew family, Anacardiaceae, that is native to Yucatán in Mexico, Central America, and South America as far south as Bolivia. Common names include Glassywood, Ronrón , and Aroeira...

), cedar (Cedrela odorata
Cedrela odorata
Cedrela odorata . The genus Cedrela has undergone two major systematic revisions since 1960. The most recent revision reduced the number of species in the genus to seven . The common cedro, Cedrela odorata L., embraces 28 other named species, including C. mexicana M. J...

), cuaulote blanco (Luehea candida),
hormiguillo (Platymiscium dimorphandrum), chicozapote (Manilkara achras), tempisque(Mastichodendron capiri) and various types of amate fig trees (Ficus
Ficus
Ficus is a genus of about 850 species of woody trees, shrubs, vines, epiphytes, and hemiepiphyte in the family Moraceae. Collectively known as fig trees or figs, they are native throughout the tropics with a few species extending into the semi-warm temperate zone. The Common Fig Ficus is a genus of...

 spp.). Under the tree cover, there is significant plant diversity including palms and araceas. Epiphyte
Epiphyte
An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...

s (air plants) are abundant as well, along with orchids, bromeliaceae
Bromeliaceae
Bromeliaceae is a family of monocot flowering plants of around 3,170 species native mainly to the tropical Americas, with a few species found in the American subtropics and one in tropical west Africa, Pitcairnia feliciana...

 and cactus
Cactus
A cactus is a member of the plant family Cactaceae. Their distinctive appearance is a result of adaptations to conserve water in dry and/or hot environments. In most species, the stem has evolved to become photosynthetic and succulent, while the leaves have evolved into spines...

. Cactus are primarily found on the vertical walls of the canyon and belong to the Ancanthocereus family. In the 1970s, tree area in a good state of conservation amounted to 3,818 hectares or 17.72% of the total land area. From 1988 to 1993, this amount was reduced to 1107 hectares or 5.35%. From 1990 to 2000, it is estimated that eight percent of the remaining forests and 38% of the rainforests were damaged. Many of the areas in good condition are broken up by disturbed areas. Most of the damage is due to illegal logging and the clearing of land for pasture or agriculture.

Medium height perennial rainforest (also known as evergreen cloud forest
Cloud forest
A cloud forest, also called a fog forest, is a generally tropical or subtropical evergreen montane moist forest characterized by a persistent, frequent or seasonal low-level cloud cover, usually at the canopy level. Cloud forests often exhibit an abundance of mosses covering the ground and...

) exists only in small dispersed patches, mostly on the sides of the canyon in contact with the Grijalva River. Many of these patches are under a hectare in size as they are located on small areas of flat land at an altitude of between 1000 and 2,500 masl. The soils are rich in un-decomposed plant matter which hold in moisture.

Low height deciduous rainforest is mostly found around the La Ceiba and La Coyota lookout points in the south and southeast sections of the park, with some in the east towards the La Chacona Cañada. These occupy a territory of 4,404 hectares in the park. Tree heights extend from four to ten meters with some as high as fifteen meters. Non tree species are not as common and mostly consist of succulent species such as Agave
Agave
Agave is a genus of monocots. The plants are perennial, but each rosette flowers once and then dies ; they are commonly known as the century plant....

, Opuntia
Opuntia
Opuntia, also known as nopales or paddle cactus , is a genus in the cactus family, Cactaceae.Currently, only prickly pears are included in this genus of about 200 species distributed throughout most of the Americas. Chollas are now separated into the genus Cylindropuntia, which some still consider...

, Stenocereus
Stenocereus
Stenocereus is a genus of columnar or tree-like cacti from the Baja California Peninsula and other parts of Mexico, Arizona in the United States, Costa Rica, Guatemala, Venezuela and the ABC islands of the Dutch Caribbean. The genus has been enlarged by the addition of species from several other...

 and Cephalocereus
Cephalocereus
Cephalocereus is a genus of slow-growing, columnar-shaped, blue-green cacti. The genus is native to Mexico. For more information see Old-Man Cactus.-Synonymy:*Haseltonia Backeb.*Neodawsonia Backeb.*Pilocereus Lem.- Species :...

. Other important species include Alvaradoa amorphoides
Alvaradoa amorphoides
Alvaradoa amorphoides is a species of plant in the Simaroubaceae family. It is a common native plant in Mexico but is also native to southern Florida, where is it endangered.-External links:* * *...

, Bursera simaruba
Bursera simaruba
Bursera simaruba, commonly known as the Gumbo-limbo, is a tree species in the family Burseraceae, native to tropical regions of the Americas from the southeasternmost United States south through Mexico and the Caribbean to Brazil and Venezuela...

, Ceiba acuminate, Bursera bipinnata, Bursera excels, Cochlospermum vitifolium, Haematoxylon brasiletto, Piscidia piscipula
Piscidia piscipula
Piscidia piscipula, commonly named Florida fishpoison tree, Jamaican dogwood or Fishfuddle, is a medium-sized, deciduous, tropical tree endemic to southern Florida, the Florida Keys, Texas, Caribbean, and Latin America. Native Americans of the West Indies discovered extracts from the tree could...

, Swietenia humilis
Swietenia humilis
Swietenia humilis is a tree species in the diverse Meliaceae family. The Genus Swietenia, the true mahoganies, is made up of three species: S. mahagoni, S. macrophylla, and S. humilis. The Latin, humilis, translates to small or dwarfish. S. humilis at 6 m. reaches one-fifth the height of S....

, Acacia collinsii
Acacia collinsii
Acacia collinsii is a species of flowering plant. It grows in secondary succession in seasonally dry ecosystems in southern Central America, where it exhibits a symbiotic relationship with several species of ant...

 and Pseudobombax ellipticum
Pseudobombax ellipticum
Pseudobombax ellipticum is a species of plant in the Malvaceae family, subfamily Bombacoideae. Common names include "Shaving Brush Tree". P. ellipticum is native to southern Mexico, El Salvador, Guatemala, and Honduras....

 .

Pine/oak forests exist in the northwest of the park in the highest altitudes, covering about 87 hectares. They are part of the same type of forest found in the Soyaló
Soyaló
Soyaló is a town and one of the 119 Municipalities of Chiapas, in southern Mexico.As of 2005, the municipality had a total population of 7,767. It covers an area of 178.9 km²....

 region it is adjacent to. They are found at an altitude of 1,200 masl and above in areas that receive precipitation of about 1500 mm per year. The most common species is the oak called Quercus conspersa, often found mixed with the two kinds of rainforest found in the park. Air plants are common here as well as well as bromeliads, orchids and plants from the Maxillaria
Maxillaria
Maxillaria, abbreviated as Max in horticultural trade, is a large genus of orchids . This is a diverse genus, with very different morphological forms. Their characteristics can vary widely....

, Lycaste
Lycaste
Lycaste, abbreviated as Lyc in horticultural trade, is a genus of orchids that contains about 30 species with egg-shaped pseudobulbs and thin, plicate leaves.- Description :...

, Cattleya
Cattleya
Cattleya is a genus of 113 species of orchids from Costa Rica to tropical South America. The genus was named in 1824 by John Lindley after Sir William Cattley who received and successfully cultivated specimens of Cattleya labiata that were used as packing material in a shipment of other orchids...

 and Laelia
Laelia
Laelia, abbreviated L. in the horticultural trade, is a small genus of 25 species from the orchid family . This is one of the most important and popular orchid genera, because of the beautiful flowers, their genetic properties and because they are fairly easy in culture. It is probably named after...

 families.

Grassland is not naturally occurring but rather exists due to human activities such as farming and livestock raising. It is seen on the north and south sides of the canyon and associated with secondary vegetation such as Tecoma stans
Tecoma stans
Tecoma stans is a species of flowering perennial shrub in the trumpet vine family, Bignoniaceae, that is native to the Americas. Common names include Yellow Trumpetbush, Yellow Bells , Yellow Elder, Ginger-thomas, and Esperanza...

, Gliricidia sepium
Gliricidia sepium
Gliricidia sepium, often simply referred to as Gliricidia , is a medium size leguminous tree belonging to the family Fabaceae...

, Plumeria rubra
Plumeria rubra
Plumeria rubra is a deciduous plant species belonging to the genus Plumeria. Its common names are Red Frangipani, Common Frangipani, Temple Tree, or simply Plumeria...

 and Acacia collinsii
Acacia collinsii
Acacia collinsii is a species of flowering plant. It grows in secondary succession in seasonally dry ecosystems in southern Central America, where it exhibits a symbiotic relationship with several species of ant...

, occupying an area of 6539 hectares in the park.

Wildlife

Over the history of the area, especially since it was definitively explored in the 1960s, the area’s wildlife diversity has been severely negatively impacted by human encroachment in the form of settlements, agriculture and hunting. However, since the federal park was established in the 1980s, wildlife diversity has increased. In 1986, the federal Secretaría de Agricultura y Recursos Hidráulicos (SARH) reported a total of ninety species of vertebrates divided into four species of fish, one amphibian, fourteen reptiles, 26 birds and forty mammals. A 2005 study indicates 308 species with four species of fish, fifteen amphibians, 195 birds, and fifty three mammals. Between these two, there have been a number of other studies which also show the growth of the number of wildlife species in the park.

Information about fish species is scarce but at least four protected species have been detected. According to a CONANP study in 2007, there are twelve species of reptile here under protection, including the river crocodile (Crocodylus acutus) and one threatened species, the Coleonyx elegans
Coleonyx elegans
The Yucatán Banded Gecko is a species of gecko found in Mexico, Guatemala, and Belize....

. Birds are the most common type of animal in the park with about 195 species documented. Six of these species are threatened and seventeen are subject to special protection. One threatened bird species in the park if the great Curassow
Great Curassow
The Great Curassow is a large, pheasant-like bird from the Neotropics. At in length and in weight, this is a very large cracid. No other cracid match its maximum weight, but its length is matched by a few other cracids....

 (Crax rubra) . Relatively abundant species include Actitus macularia, Dendrocygna autumnalis, Egretta caerulea, Egretta thula, Tachybaptus dominicus and Coragyps atratus, all of which are associated with bodies of water. There have been fifty three species of mammals detected recently in the park, of which two are considered to be threatened, two in danger and two subject to special protection. Endangered and threatened species include the spider monkey(Ateles geoffroyi), jaguarondi, the ocelot
Ocelot
The ocelot , pronounced /ˈɒsəˌlɒt/, also known as the dwarf leopard or McKenney's wildcat is a wild cat distributed over South and Central America and Mexico, but has been reported as far north as Texas and in Trinidad, in the Caribbean...

, the lowland paca, the white-tailed deer
White-tailed Deer
The white-tailed deer , also known as the Virginia deer or simply as the whitetail, is a medium-sized deer native to the United States , Canada, Mexico, Central America, and South America as far south as Peru...

, the anteater (Tamandua tetradactyla) and the buzzard (Sarcorhampus papa) . The most abundant species include the bat Artibeus jamaicensis and the rat peromyscus mexicanus .

Conservation issues

The most important conservation issue in the park is the contamination of the Grijalva River
Grijalva River
Grijalva River, formerly known as Tabasco River. is a 480 km long river in southeastern Mexico. It is named after Juan de Grijalva who visited the area in 1518. The river rises in Chiapas highlands and flows from Chiapas to the state of Tabasco through the Sumidero Canyon into the Bay of...

, which passes through the Sumidero Canyon proper. However, other threats to the park include human encroachment and other human activities. An estimated 1500 to 2000 hectares, or about six percent of the park total, have been encroached upon, mostly by illegal human settlements next to the city of Tuxtla Gutiérrez since the park was established. It is estimated that about 15,000 people live within the park’s borders. Most of these illegal constructions belong to the very poor who have migrated to the city from elsewhere. The demand for living space has created an industry of illegal subdivisions which are then sold without the proper title to victims. Three of the main neighborhoods to develop in this way are the Patria Nueva Alta, Arroyo Blanco, La Esperanza and Las Granjas. The encroachment is a result of the fast population growth of Tuxtla Gutiérrez and Chiapa de Corzo. The growth of these areas has led to land ownership disputes, loss of wild habitat and deforestation. In 2002, the federal and state government signed an accord to remove illegal human settlements and work to prevent further encroachment. Operations to evict illegal settlers have been carried out such as a 2005 operation which evicted about one hundred people and others that have prevented new settlements from getting established. However, the encroachment of human settlements into the park from the city of Tuxtla Gutiérrez has been so damaging that a 2007 report states that there is no other alternative than to deregulate this section of the park and work to prevent further incursion. However, the situation has not been helped by the fact that there are disputes over the boundaries of the park as decreed in 1980. Since 2009, there have been further efforts by park management to stop the advancement of these illegal settlements as well.

Despite this, a number of areas in the park are well-conserved mostly due to the very rugged terrain.

In addition to the illegal settlements, there are legal settlements and operations which affect the park. There are eight ejido
Ejido
The ejido system is a process whereby the government promotes the use of communal land shared by the people of the community. This use of community land was a common practice during the time of Aztec rule in Mexico...

s which border the parks and whose activities directly affect it: San Antonio Zaragoza, Venustiano Carranza, Francisco Sarabia, Gabriel Esquinca, Benito Juárez, Osumacinta, El Palmar, 16 de Septiembre and Nuevo Bochil. Established before the park, there are still five ejidos and three human settlements established within, Libertad Campesina (population 495), Nueva Esperanza (139), La Unión (329), El Paraíso (134), Tierra Colorada (199), La Candelaria / Triunfo Agrarista (631). As of 2005, the total population within the park’s borders was 1927. Because of human activity, this park is one of the most susceptible to wildfires, and the most damaged by such in Mexico from 2009 to 2011. Many of these were started by human activity in or near the park such as one fire set on a nearby farm in May 2011.

In addition to this, there are lime and other extraction operations within the park’s borders. They exist legally because they had been there well before the park was established. However, these operations have destroyed about 2,600 hectares. These operations produce noise, smoke, dust and small tremblers from explosions used to extract the minerals. Much of the environment damage come from runoff from mining waste which winds up in the Grijalva River. However the dust and smoke have produced a distinct white coating on surrounding flora.

Tourism

The scenery of the canyon has become a major tourist attraction for the state, with developments for eco tourism and extreme sports. The navigable part of the Grijalva River is mostly used to ferry visitors into the canyon area. The park has six lookout points accessible by land called La Ceiba, La Coyota, El Roblar, Tepehuaje, Los Chiapas and Manos. In the rainy season, tourism is enhanced by the activity of waterfalls such as the Árbol de Navidad, Cueva del Hombre, Cueva del Silencio, Cueva de Colón, Cueva de Colores and Cueva del Suspiro. A lesser known attraction is the archeological site called the Ruins of Berlin. The most important economic activity in the canyon is ecotourism
Ecotourism
Ecotourism is a form of tourism visiting fragile, pristine, and usually protected areas, intended as a low impact and often small scale alternative to standard commercial tourism...

. Most of the visitors are Mexicans. Weekends are busiest with local and regional visitors to bike, swim, hike, camp and picnic.

The canyon is the second most visited site in Chiapas, after Palenque
Palenque
Palenque was a Maya city state in southern Mexico that flourished in the 7th century. The Palenque ruins date back to 100 BC to its fall around 800 AD...

 . The park is visited annually by 300,000 people about 80% are from Mexico and the rest from abroad. During vacation times, the park may be visited by anywhere from 1,000 to 7,000 people per day, who either enter by car to go to the lookout points or enter by water by boat from Chiapa de Corzo
Chiapa de Corzo
Chiapa de Corzo may refer to:*Chiapa de Corzo - a Mesomerican archaeological site located in the Chiapas highlands, Mexico*Chiapa de Corzo, Chiapas - the modern township and municipality, central Chiapas, Mexico...

. Entrance and boating fees can generate about 70,000 pesos per day for cleanup efforts. The number of visitors to the park hit a peak in 2003 with about 196,500.

Commercial activity in the park is limited to those which serve tourists, sales of food and Mexican handcrafts and folk art
Mexican handcrafts and folk art
Mexican handcrafts and folk art is a complex collection of items made with various materials and intended for utilitarian, decorative or other purposes. Some of the items produced by hand in this country include ceramics, wall hangings, vases, furniture, textiles and much more...

. Tour operators are organized into cooperatives, with food and craft vendors working independently. These merchants must receive an annual permit in order to operate within the park’s borders. The most important of these businesses are the boats which ferry people through the canyon along the Grijalva River. Most of these boat tours operate out of Chiapa de Corzo and run along the river to the Chicoasén Dam
Chicoasén Dam
The Chicoasén Dam is an embankment dam and hydroelectric power station on the Grijalva River near Chicoasén in Chiapas, Mexico. The dam's power plant, known as "Manuel Moreno Torres" contains 5 x 300 MW, 3 x 310 MW Francis turbine-generators. Torres was Comisión Federal de Electricidad's Director...

 for a distance of about thirty km. Chiapa de Corzo has two main docks for this activity. The largest and oldest is called Cahuare, with paved areas and a restaurant. The second smaller one also has restaurants but it also has a swimming area as well. These two docks host six tour cooperatives, with about 120 boats that can hold between ten and forty passengers each. As they take visitors from Chiapa de Corzo or Tuxtla Gutierrez through the canyon and to the dam, providing environmental, historical and cultural information. These are the most organized tourist activity in the park.

A spate of accidents involving these boats occurred from late 2009 to early 2010, claiming the lives of six tourists and hurt sixty two others. The accidents occurred on decrepit boats, many of which were operating without permission with underage or unlicensed crew members. There were no ambulance boats and no first aid services on shore. Two of the cooperatives, Ángel Albino Corzo and Nandiume were suspended and fined for the accidents, taking about sixty boats out of operation. These boating accidents caused significant problems for the tourism industry.

For those who choose to see the canyon from the lookout points above, there are restaurants and other food service places as well as camping and picnicking facilities.

The other two attractions of the park are general ecotourism
Ecotourism
Ecotourism is a form of tourism visiting fragile, pristine, and usually protected areas, intended as a low impact and often small scale alternative to standard commercial tourism...

 and extreme sports. The park has hiking paths and sports fishing is allowed sporadically by permit. There are some locations that rent kayaks and other boats. The Amikúu Ecological Park is located within the canyon area, which is accessible by boat from Chiapa de Corzo. The park is divided into three parts; Discover the Canyon, Colors of Chiapas, and Area of Adventure. The first is located in the dock area, with a demonstration of the history of the canyon and a video of its geological formation. There is also a souvenir shop here. The interior of the park contains a 300 meter long zip line. Colors of Chiapas is a small museum which exhibits the traditional dress and native musical instruments of the state’s indigenous peoples. The Area of Adventure takes visitors on a tour of the rainforest area, which include a suspension bridge. It also has a herpetarium
Herpetarium
A Herpetarium is usually a building at a zoo or private collection which displays different species of reptiles and amphibians.- References :...

, an aviary and enclosure for jaguars and one for crocodiles. The park was opened in 2009 at an initial cost of 120 million pesos.

Extreme sports include mountain biking, rappelling, spelunking and more. Rappelling allows for access to many of the canyon’s small caves which are not accessible any other way. The dam area has recreational fishing with an annual tournament. One major annual event is the Copa Mundo Fino swimming marathon. An Australian base jumper
BASE jumping
BASE jumping, also sometimes written as B.A.S.E jumping, is an activity that employs an initially packed parachute to jump from fixed objects...

 plunged to his death in 2006 after jumping off an 800 meter cliff in the canyon. The accident occurred during a sanctioned event sponsored by an energy drink
Energy drink
Energy drinks are beverages whose producers advertise that they "boost energy." These advertisements usually do not emphasize energy derived from the sugar and caffeine they contain but rather increased energy release due to a variety of stimulants and vitamins....

 maker with jumpers from Australia, the U.S., Europe and Mexico.

History and archeology of the area

The history of the area is connected to the Chiapa people, who occupied the Central Valley area before the arrival of the Spanish. The origin of these people is not known, but theories have them migrating north from Nicaragua
Nicaragua
Nicaragua is the largest country in the Central American American isthmus, bordered by Honduras to the north and Costa Rica to the south. The country is situated between 11 and 14 degrees north of the Equator in the Northern Hemisphere, which places it entirely within the tropics. The Pacific Ocean...

 or even Paraguay
Paraguay
Paraguay , officially the Republic of Paraguay , is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to the east and northeast, and Bolivia to the northwest. Paraguay lies on both banks of the Paraguay River, which runs through the center of the...

. Their main settlement was in Chiapa de Corzo near the canyon, with a fortified area in the higher areas in the canyon for protection from invasions. The Chiapa fiercely resisted Spanish conquest and were not subdued until the arrival of Diego de Mazariegos in 1528. Their last refuge was in the fortified area, now known as the archeological site of the Ruins of Berlin. Here the last of the Chiapa held out from 1528 to 1535 after the Spanish took over the main city. Legend states that when this last fortification fell, the remaining Chiapa committed collective suicide by jumping into the canyon. Since then, the canyon has served as a boundary marker between the Zoque and Tzotzil peoples.

Until the 20th century, the canyon area was relatively unexplored. In 1895, three Frenchmen attempted to explore the canyon but were drowned in the river. An American came in 1932 but also perished. This gave rise to legends about witchcraft in the areas as well as the ferocity of the area’s crocodiles. In 1960, an expedition of soldiers from the Mexican army, nicknamed the “red handkerchiefs” succeeded into crossing through the canyon by boat over twenty km. This opened up the canyon to local exploration and exploitation, including rudimentary tourism and the hunting of crocodiles and other native fauna.

There has been little archeological work done in the area. The main site is called the Ruins of Berlin, named after German explorer Heinrich Berlin, who visited the area in 1946 and named the area “Sumidero. This site is located seven km from the Belisario Domínguez Bridge in Tuxtla on the edge of the river. It covers an area of 467 by 60 meters, bounded by small mounds surrounding patios. The original description of the site was undertaken in 1923 and 1932 by Becerra, who called it Chiapa Viejo, and stated it was the capital of the Chiapa people. However, Remesal in 1966 determined it was a secondary site. The last major survey was done in 1976 by Alejandro Martínez, discovering that there are twenty four individual sites of which nine are mounds and fifteen of which are in caves. One of these contains cave paintings which indicate that the area has been occupied since at least the very early Pre Classic period
Mesoamerican chronology
Mesoamerican chronology divides the history of pre-Columbian Mesoamerica into several periods: the Paleo-Indian , the Archaic , the Preclassic , the Classic , and the Postclassic...

.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK